Dental posts are known having a head portion to allow the building of a tooth prosthesis thereon and are typically implanted in the root canal with the intent that they remain there for the life of the patient. Several types of posts are known to deal with the anomalies that are found in various teeth. One type, e.g. U.S. Pat. 3,919,774, employs an external screw thread to allow the post to cut a groove into the walls of the previously prepared open root canal. Others, e.g., U.S. Pat. 4,729,736, employ a helically grooved external surface which act as flute lines for escape of air and which, together with other structures, engage an adhesive inserted into the root canal thereby making the loosening of the dental post under the extreme stress of chewing less likely.
It has also been known to have to remove dental posts from a root canal. This has typically been necessary whenever an infection occurs along the previously cleaned root canal or where there has been post breakage, typically of the head portion. This presents a very difficult problem since the post is designed to remain and not to be removed. Typically the endodontist has to drill a bore having a diameter greater than that of the post thereby destroying the post. This is difficult because of the hardened materials (usually stainless steel or titanium) of which the post is made and may require grinding the post and greatly enlarging the root canal opening in the process. Such enlarging is done at the expense of the material forming the side wall of the tooth and results in the weakening of the tooth due to the future insertion of a dental post in the same root canal.